When a natural resource is available at a remote site, it is frequently required to set up an industrial plant to treat the natural resource without the usual infrastructures and utilities available. In particular, when the site is close to the sea in a desert area, it is desirable to use seawater for cooling purposes on the site and to minimize the consumption of soft water.
The present invention allows the use of an impure source of water for cooling purposes in an industrial plant.
Industrial plants frequently include an air separation unit. Such plants commonly chill down cooling water by direct contact with a waste gas from the air separation unit and then cool down a compressed air flow by direct contact with the chilled water. This latter direct heat exchange between chilled water and compressed air requires a water quality which cannot be met by impure water, such as, for instance, seawater.
The solution to the problem is to use a waste gas of the air separation plant to chill the impure water (e.g., sea water) by direct contact between impure water and the waste gas, and then to exchange heat between the impure chilled water and a closed circuit of soft water. The produced chilled soft water can then be used for cooling the airflow by direct contact.